Nickel / chromium (Ni/Cr) ion sputter standard

This standard consists of 12 alternating layers: six layers of chromium approximately 53nm thick, and six layers of nickel 64nm thick on a silicon wafer. The total thickness is 700 nm with a maximum variation across the 75mm production wafer of ±2%. The section of polished silicon wafer is 1 x 3 cm. The mass density of the chromium and nickel was determined using electron beam excitation and then by measuring characteristic X-ray intensities.